1. Field of the Invention
This invention generally relates to bicycle hydraulic brake actuation device. More specifically, the present invention relates to bicycle hydraulic brake actuation device that provides improved braking characteristics in a braking system.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One system that has been extensively redesigned is the hydraulic brake system.
The bicycle hydraulic brake system typically includes the hydraulic brake actuation device, a rotor attached to one of the bicycle wheels and a caliper adjacent to the rotor with brake pads that selectively contact the rotor in response to changes in hydraulic pressure in the hydraulic brake actuation device.
The hydraulic brake actuation device typically has a housing mounted the bicycle handlebar. The housing includes a bore, a master piston disposed in the bore and a lever arm pivotally supported on the housing. Pivoting movement of the lever arm provides leverage for moving the master piston causing changes in the hydraulic pressure and movement of a slave piston in the caliper. Typically, the brake pads are spaced apart from braking surfaces of the rotor until urged into braking contact with the rotor by movement of the slave piston.
When the lever arm of the hydraulic brake actuation device is initially moved, braking contact is delayed because the brake pads must first move and close the gap between the brake pads and the braking surfaces of the rotor. The movement of the brake pads typically corresponds directly movement of the lever arm in a movement ratio. Specifically, for each angular degree of movement of the lever arm, there is a corresponding movement of the brake pads.
It is desirable to have the brake pads move quickly toward the braking surfaces of the rotor in order to provide rapid braking response. However, in conventional hydraulic brake actuation devices, movement of the pads to the rotor requires an undesirable amount of lever arm travel.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved hydraulic brake actuation device that provides improved ratio of the movement of the brake pads relative to the movement of the lever arm. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.